Process of producing coated or other thin metallic sheets



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v H. C. HARRISON PROCESS OF PRODUCING GOATEDOR OTHER TH IN METALLIC SHEETS Filed May 21, 1925 2 Sheets-Sheet 1 awe/Idiot April 13 1926.:

P ROCESS 0F PRODUCING COATED OR OTHER THIN METALLIC SHEETS I Filed May 21, 1925 2 Sheets-Sheet 2 H. C; HARRISON i water-tight.

' duced Patented Apr. 13," 1926.

1 UNITED STATES HERBERT CHAMPION HARRISON, 0F LOCKPORT,

NEW YORK.

PROCESS OF PRODUCING COATED OIt/OTIIEB THIN METALLIC SHEETS.

Application filed m 21, 1925. Serial No. 31,921[

To all whom it may concern:

Be it known that I, HERBERT CHAMPION HAnmsoN, a subject of the King of Great Britain and Ireland, residing at the city of Lockport, in the county of Niagara and State of New York, have invented certain new and useful Improvements in Processes of Producing Coated or Other Thin Metallic Sheets, of which the following is a full, clear, and exact description.

This invention relates to the manufacture of thin sheets of ductile metal, such as copper, and, more specifically, to a process, including an electrolytic step, for making metallic sheets having a protective film or coating on one side only.

In the production of metallic sheets electrolytically, it has been customary to perform such finishing operations upon sheets as are deemed necessary after the sheets have been stripped from the cathode surfaces.

I have found that electrolytically prosheets may be'more economically and conveniently finished, for many purposes, before they have been stripped from the cathode, and that a burnishing treatment applied to the deposited layers on the cathode will accomplish the further useful function of loosening the layer from the cathode, and will facilitate the stripping operation.

Furthermore, there are many uses for thin sheets, as of copper, coated onone side only with a thin' film of protective materiah'suoh as tin, zinc or lacquer. For example, in making radiators for motor vehicle engines, it is highly desirable to use thin co per strips of about five one-thousandthso an inch in thickness, and approximately three to four inches in width, which are coated with tin. The tin coating facilitates the dipping process by which the contacting surfaces of the radiator elements are soldered or metallically united, and made Surfaces of radiator elements coated with tin offer great resistance to corrosion by alkaline water which so frequently is used in the cooling system of the motor v hicle engine. There is, however, no advantage in tinning the strips on both sides. Only the side in contact with the circulating water of the cooling systems needs this rotection. Hence all the advantages obtainable from tinning the radiator elements is realized by tinning one side'of the strip. It, therefore, a cheap, commercially workable method of tinning sheets on I one side only is available, a considerable benefit would accrue in the more economical production of tin-coated radiators.

The practical difficulties of applying a coat of tin to one side only of a sheet at a cost low enough to render it available for ordinary demands have never, to my knowledge, been overcome.

By the method hereinafter described, thin sheets-of copper, having a film of tin on one side, may be produced b depositing copper electrolytic-ally upon a sheet metal cathode, I dipping the compound sheet thus formed in a tinning bath, then burnishing the tinned surfaces by giving said compound sheet a progressive working operation suflicient to -burnish the surfaces of the layers and loosen the layers from the cathode, and then stripping the layers from the cathode sheet to form two sheets of thin copper, each having a thin film of tin on one side only.

In the accompanyingdrawings, in which like reference characters indicate like parts throughout the several views:

Fig. 1 is a diagrammatic illustration of an electrolytic? apparatus for depositing metal- 11c layers upon both sides of a cathode sheet of indefinite. length;

Fig. 2 is a diagrammaticillustration of an apparatus for coating the compound sheet produced in the electrolytic apparatus;

Fig. 3 is a diagrammatic illustration of one apparatus for burnishing and strip ing the electrolytically deposited layers to orni two thin sheets;

Fig. 4; is a diagrammatic illustration of a preferred apparatus for accomplishing the same result as the apparatus shown in Fig. 3;

Fig. 5 is a view of the electrolytic cell 1, viewed from the left; and

shown in Fig.

do View of rolls shown in Fig. 6 is a si Fig.4. 1

In Fig. 1. numeral 10 indicates an electrolytic cell beneath which isa catch-pan 11,

adapted to receive electrolyte flowin from i In this diagram the electrddyte is being continuously circulated through pipe 13 into one the cell.

indicated as from the tank 12.

end of the cell 10, and out from said cell through openings that admit the passage. of the thin traveling cathode sheet or ribbon 15, into the pan 11, whence it is pumped by an acid-proof pump 14 through pipe 16 to tank 12, thus completing the circuit. In this diagram, 17 indicates a spool from which the ribbon cathode is unwound, and

18 a mechanically-driven reel by which the ribbon cathode may be drawn from the spool 17 (which may, if desired, be' so mounted as to apply tension to the rlbbon), through the cell at any regulated speed necessary. Suitable connections between the anode and cathode and a source of current, (not shown) may be made at 19 and 19" respectively; the latter necessarlly being in the form of a brush or slip connection. The compound sheet consisting of the oathode ribbon and deposited layers, is indicated at 15.

After the entire length of the cathode ribbon has been plated with a layer, say five one-thousandths of an inch thick, or of any suitable thickness, the roll of compound sheet or strip 15, consisting 0t the cathode strip sandwiched between two deposited layers, may be placed upon another reel or spool, and said compound strip unwound therefrom and passed progressively through a bath of liquid coating material, and then the layers may be burnished progressively and stripped; or, in the event that it is not desired to produce sheets coated with a protecting film on one side, the roll. of compound strip may be placed upon a spool, the end passed between working and burnishlng instrumentalities, and the strip then subjected progressively to a burnishing, la erloosening .and stripping process. The e ges of the compound strip may, if desired, be sheared or otherwise trimmed, but it is preferred to crack or weaken the bond between the layers at the edges by working the strip.

If it is desired to produce, for example, tin-coated sheets of metal, the roll of compound strip or sheet 15 may be placed upon a delivery spool 20, as indicated in Fig. 2, and lead into and through a suitable fluxing bath 21, around guide-rolls 22, and thence into and through a tinning bath-23, around guide-rolls 24. From the tinning bath, the compound sheet, now having a coating of tin and designated by 15", is led between suitable scrapersor doctors 25, and squeezing rolls 26, to remove excess of coating from the com oundstrip 15 and direct such exccss bac into the bath, as is usual. The strip 15 may then be led over a ide-roll 27 and finally wound upon a spoo 28.

For the purpose of burnishing the surfaces of the strip or sheet 15 or 15*, whether it-be coated with a protecting film or not, and loosening the adhesion of the layers, a roll of said compound strip maybe placed upon a deliver reel or spool 30, and one end led through the pass of a pair of plain faced rolls 31, set to exerta pinch upon the compound strip suflicient to burnish its surface and apply enough reducing or working ressure to cause a slight localized molecular ow adequate to loosen the adhesion of the layers to the cathode strip, .and sufiicient to crack and weaken or sever the bond between the layers upon opposite sides of the cathode strip where they unite around its edges. The loosened layers may be peeled fromthe cathode strip after the advance end has been fed through the roll'pass and between the guides 32, and each stripped layer 15, as an 1nde endent sheet, may be attached to a win ing reel 33. The advance end of the cathode strip 15 from which the deposited layers have now been separated, may be attached to reel 34. Now as the compound strip transverses the roll pass, drawn through it by the bite of the revolving rolls upon 1t, the stripping reels 33 may be caused to strip the layers 15 from the cathode sheet 15, and wind them into coils; and the reel 34 may assist the passage of the compound strip through the roll pass, and wind the cathode strip in a roll of cathode strip suitable to be used again to receive a new deposit in the electro ytic cell.

A preferred method of loosening the layers is to work the layers by repeatedly flexmg the compound stri There are many instrumentalities whereli complished. In Fig. 4 for thus working the compound strip to loosen the layers and at the same time burnish their outer surface. In Fig. 4, 30 indicates a roll or spool of compound strip, 15 or 15', consisting of a cathode core plated with layers of copper, for example, either coated or uncoated. The compound strip may be threaded between bars or rolls 31 staggered with respect to each other and adjusted to cause the strip to assume a wavy or zigzag form between them. The bars or rol s 31 may be arranged in two series, which maybe adjusted toward} or from each other. The compound strip may be drawn from the spool between the bars or rolls 31 thereby progressively flexing it repeatedly in opposite directions during its progress, thus loosening the layers from the cathode strip and weakening or cracking the bond between the layers at the edge of the compound strip by working the layers so that the layers may be readily stripped from the cathode. The stripped layers may one means is shown be separately wound, as sheets of copper 15 (coated or uncoated), on revolving spools or reels 33 while the cathode core of the compound sheet is being wound on reel 34 and drawn between the rolls or bars of the working instrumentality.

If desired, in order to draw or assist in drawing the compound strip through or between the flexing elements 31, the sheet may be subjected to pressure between pinch y this may be ac .rolls 35, which may have the additional function of further weakening or. cracking the bond between the layers at the edges of the compound strip. The rolls 35 may be so formed as to app y pressure only to the edges of the compound sheet if desired, as indicated in Fig. 6. I

The rubbing or rolling pressure on the outer surfaces of the compound strip as it is being drawn between the working elements will have a burnishing effect if the adjustment of said elements is such that plication of the invention,

adequate friction is applied.

A cathode strip' of copper eight inches in width, iive onc-tho-usandths of an inch in thickness and'of indefinite length, has been found suitable for the purpose. In the manufacture of copper sheet for use in radiators these dimensions are desirable be cause they are those of standard rolled stock used in manufacture and When damaged by use as cathodes they can be cut up and used for making radiating elements. Althou h it is possible to strip the deposit from a hig ly burnished metallic cathode surface, it may be desirable to apply a coating to the surface before subjecting it to the electrolyte. Many kinds of coating material are known for this purpose. I have found sodium sulphide a satisfactory cathode coating material.

Although the process been described and illustrated for the purpose of disclosing in detail one useful. ap-

it is not intended to be limited to a particular kind of deposited metal or a particular kind of coating film, as the principle of the invention has a much broader application. 7

What I claim and desire to secure by Letters Patent of the United States is as follows:

1. The method of producing thin metallic sheets which comprises depositing a layer of ductile metal electrolytically upon a cathode sheet, then subjecting the compound sheet thus formed to a working operation applied progressively, thereby loosening the deposited layer from the cathode sheet, and then stripping the layer from the cathode sheet.

2. The method of producing thin metallic sheets, which comprises depositing a layer of ductile metal electrolytically upona cathode sheet, then subjecting the compound sheet thus formed to working by progressively flexing it in opposite directions, thereby loosening the layer from the cathode sheet.

3. The method of producing thin metallic sheets which comprises depositing a layer of ductile metal electrolytically upon each side of a cathode sheet, then subjecting the compound sheet thus formed to a working operation applied progressively, thereby of this invention has loosening the deposited layers from the oathode sheet, and then stripping both layers from said cathode sheet.

4. The method of producing thin metallic sheets which comprises depositing an envelope of ductile metal electrolytically around a cathode sheet, then subjecting the compound sheet thus formed to a working operation applied progressively, thereby loosening the layers of the envelope adhering to the surfaces of the cathode sheet and cracking the connecting bond at the ed es 5. The method of producing thin metzillit sheets which comprises progressively depositing an envelope of ductile metal around an'elongated flexible cathode by causing it to progress from end to end through an electrolytic bath, progressively severing the envelope on the cathode longitudinally into two layers, then stripping said layers from the flexible cathode.

6. The method of producing thin metallic sheets which comprises depositing an envelope of ductile metal electrolytically around a cathode sheet, then subjecting the compound sheet thus formed to working by progressively flexing it in opposite directions, thereby loosening the layers of th( envelope adhering to the surfaces of the cathode sheet and cracking the connecting bond at the edges.

7'. A method of producing thin metallic sheets having a protective coating on one side, which com rises depositing a layer of metal electrolytically upon a cathode, dipping the body so formed into a bath} of liquid coating material, and stripping the metallic, coated la or from the cathode.

8. A method 0 producing thin metallic sheets having a protective coating on one side, which comprises depositing a. layer of metal electrolytically upon a cathode sheet, dipping the compound sheet so formed into a bath of liquid coating material, and stripping the metallic, coated layer from the cathode sheet.

9. A method of producing thin metallic sheets having a protective coating on one side, which com rises depositing a layer of metal electrolytically upon each side of a cathode sheet, dipping the compound sheet so formed into a bath of liquid coating material, and stripping the metallic, coated layers from the cathode sheet. 7 10. A method of producing thin metallic sheets having a protective coating on'one side, which comprises depositing an envelope of metal electrolytically around a cathode sheet, dipping the compound sheet thus formed in a bath of liquid coating material and then cracking the envelope at its edges and stri )ping the surface layers from said cathode sheet.

11. A method of producing thin metallic sheets having a protective coating on one side, which comprises depositing an envelope of metal electrolytically around a cathode sheet, dipping the compound sheet thus formed in a bath of liquid coating matrial, severing the envelope while on the cathode sheet into two layers, one on each side of the'calhode sheet, and stripping the severed layers from said cathode sheet.

12. A method of producing thin metallic sheets having a protective coating on one .side, which comprises depositing a layer of ductile metal electrolytically upon a oathode sheet, dipping the compound sheet thus formed into a liquid bath of suitable protective material, then subjecting the compound, coated sheet to a working operation progressively applied, thereby burnishing the metallic coating and loosening the layer from the cathode sheet, and then stripping the coated layer.

13. A method of producing thin metallic sheets having a protective coating on one.

side, which comprises depositing a layer of ductile metal electrolytically upon a cathode sheet, then treating the surface of the layer to cause adhesion of a metallic coating, dipping the compound sheet thus formed into a liquid bath of suitable protective metal, then subjecting the compound coated sheet to a working operation progressively applied, thereby burnishing the metallic coating and loosenin the layer from the cath ode sheet, and then stripping the coated layer therefrom.

14. A method of producing thin metallic sheets having a protective coating on one side, which comprises depositing an envelope of ductile electrolytically around a cathode sheet, dipping the compound sheet thus formed in aliquid bath of suitable coating metal, then subjecting the compound sheet to a working operation progressively applied, thereby burnishing the metallic coating, loosening the layers of the envelope from the surfaces of the cathode sheet and cracking the connecting bond of the envelope at the edges, and finally stripping the layer from the cathode sheet.

15. A method of producing thin metallic sheets by rogressively' depositing metal electrolytica ly upon a, cathode in a coherent layer, thenstripping the layer from said cathode in the manner substantially as described.

'In testimony whereof, I hereto afiix my signature.

HERBERT C. HARRISON. 

